In U.S. Pat. No. 263,920 which issued Sep. 5, 1882, R. J. LaGrange discloses a structure for a ring. In this ring, an expansible and contractile band is provided with a rack and pinion and a locking head. In this head, the ends of the band pass through hollow or grooved sections and are controlled by cooperation between the rack and pinion for adjusting the size of the ring. A head portion is furthermore provided which is adapted for being engaged by a key or some other such implement so that the pinion can be rotated so that the ends of the band are moved in or out of the head portion thereby contracting or expanding the band. This ring structure requires a flexible material for constituting the band which of necessity is of a limited thickness and cannot be rigid in structure. The flexibility of the band may permit the adjustment described but, if the material of the band were to be thick and substantial, such a construction could not assume the relative positions necessary to enable the rack and pinion to work properly.
In U.S. Pat. No. 3,228,208, M. Silverman discloses an adjustable finger ring which is subject to the same criticism. Therein, a band is provided the ends of which pass into a space wherein teeth are located. One of the ends of the band has a hole therein accommodating a small ball or bead which can be displaced radially to occupy positions between spaces intermediate a number of teeth or projections. The band which is provided must necessarily be flexible to a substantial degree to accommodate the operation which is described. If the band were to be of a substantial material, the ends of the band could not assume the attitudes necessary for the ends of the band to be accommodated in the aforementioned space. Thus, the nature of the materials which can be employed in fabricating the ring which is described is severely limited.
H. Bollinger discloses a flexible band for a watch in U.S. Pat. No. 4,615,185. A bracelet clasp is provided which includes a sleeve attached to one of the bracelet tongues. The sleeve includes transverse teeth which cooperate with complementary teeth positioned on the other tongue of the bracelet. These teeth are disposed in what could be described as a radial attitude. The sleeve is elastically deformable in order to allow radial displacement and thereby disengagement of the teeth for the opening of the bracelet.